RFR: 8331873: Improve/expand info in `New API In` on Help page

[Nizar Benalla]

This PR supersedes #19222, I've resolved the merge conflicts and updated the text based on review comments.

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Commit messages:
 - Update according to feedback
 - Merge branch 'master' into new-api-help-page
 - QOL change - change "all" to "toggle all" in the new-list and deprecated-list pages
 - fix merge conflicts and slight refactor due to 8335122
 - 8331873: Improve/expand info in `New API In` on Help page.

Changes: https://git.openjdk.org/jdk/pull/23269/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=23269&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8331873
  Stats: 42 lines in 3 files changed: 34 ins; 2 del; 6 mod
  Patch: https://git.openjdk.org/jdk/pull/23269.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/23269/head:pull/23269

PR: https://git.openjdk.org/jdk/pull/23269